The present invention relates to noise abatement apparatus and a method of reducing noise levels and, more particularly, to a noise abatement apparatus and method for yarn treating machines which texture yarn at high production speeds.
It is well known that in many industrial operations workers are exposed to dangerously high noise levels which, over a period of time, can result in hearing impairment. It has also been known that worker productivity is adversely affected where the working conditions involve exposure to high levels of noise. As a result, various industrial and governmental bodies have proposed and enacted regulations and guidelines which require businesses to modify the production environments of their employees by reducing the sound levels to which the employees are exposed.
As a result of these regulations, resort has been had to the use of individually worn ear protectors or the use of sound baffles around various types of machinery.
The former solution has been found impractical due to the resistance of workers to consistently employing the ear protectors, and, since it is impractical to monitor machine operators to ascertain whether or not they are properly wearing ear protectors, of necessity, noise abatement techniques have been directed to installing various types of sound baffles around noise generating sources.
In a number of arrangements, it has been proposed to surround either the entire machine with a sound baffle or enclosure, or to mount sound absorbing panels on the machine to enclose the device which is the greatest sound generating source.
The technique of completely enclosing a piece of machinery, however, is practical only where the machinery is relatively cool running, i.e., non-heat generating, which is such a rare occurrence as to render this procedure of extremely limited utility.
The other proposed techniques of enclosing all or at least most of the principal noise generating sources of a machine have suffered from the disadvantages that such procedures encumber the use and operation of the machines by restricting access to the portions of the machines that require operator attention as well as contribute to heat build-up in the enclosed parts, thus requiring compensating and expensive cooling devices. Such cooling devices appreciably increase the cost of installing the sound insulating equipment which itself is an expensive undertaking, but which, nevertheless, is rendered necessary in the interest of preventing hearing impairment as well as augmenting productivity.
The following references are representative of the prior art:
3,393,765 3,747,735
3,604,531 3,782,087
3,633,706 3,860,086
3,695,386 3,866,708
3,700,068 3,867,875
3,713,509
The present invention provides solutions to the foregoing problems without encountering the drawbacks of the prior art arrangements by concentrating its improvements on a specific type of noise generating machinery, i.e., a false twist texturing machine, whereby a satisfactory noise reduction is achieved by substantially fewer modifications to the machine than would be the case where the prior are techniques are employed.
Specifically, the present invention is directed to noise abatement in connection with a false twist texturing machine of the type that is provided with a number of yarn texturing positions each of which is provided with yarn feeding means for drawing yarn from a take-up package through a heater and false twist spindle and then delivering the yarn to a yarn take-up package.
Noise abatement techniques as applied to false twist machines, it has been found, must take into consideration certain operational aspects of these machines, such as the fact that large quantities of heat are continuously generated by the heaters of the machines which must be dissipated so that the working environment may be maintained at a tolerable level. Additionally, access to the supply packages, heater, spindle and take-up packages must be continually provided for observation by an operator, so that any yarn breakages which frequently occur in these machines can be promptly rectified so as to minimize production losses and to avoid expensive fouling of the machine. As will be appreciated by those skilled in the art of texturing, presently operated false twist machines run at enormously high speeds corresponding to a yarn velocity through the machine on the order of 400 yards per minute, on the average. As a result, the noise generated by the moving parts of these machines are presently manufactured, can result in hearing impairment for an individual who is exposed to machines on a day-to-day basis.
According to the present invention, it has been found that substantially few modifications to a false twist texturing machine need be effected in order to bring the noise level of the machine operating at capacity within tolerable limits. Also, the cost of the modifications that are effected is substantially lower than that which would be the case if the total enclosure procedures were followed so that the present invention provides the economic incentive necessary to encourage manufacturers to adopt the sound suppressing method as described herein.
Specifically, it has been found that a significant noise level reduction can be achieved in yarn texturing machines where a number of relatively simple modifications to the machine are made. Specifically, according to the present invention, noise generated by tape pulleys is eliminated by appropriate modification of the pulleys and by enclosing in a suitably muffled enclosure the head end tape pulley. Additionally, tunnels are provided for the drive belt of the tape pulleys at a specific location with the tunnels being lined with sound absorption material so that noise generated within the gear housing will be attenuated in the tunnels. Also, the idler pulleys which are driven by the drive belt are provided with vibration isolation mountings and sleeves, the latter serving both to increase the diameter of the pulleys and thus reduce their rotational speed and to provide a dissimilar outer metal casing which will serve as a sound impedance barrier and frictional damper.
Also, according to the invention, all unnecessary openings in the gear housing are closed with panels which are mounted on the interior or exterior of the housing. Also, the inside surfaces of the gear housing should be lined with a sound absorption material.
Preferably, the conventional plastic sheet protectors that are provided with a conventional false twist machine as a protection for an operator and which are located adjacent the spindles can also be lined with a suitable sound adsorption material and these deflectors should be repositioned as closely as possible to the spindle heads.
Additional noise suppressing procedures, which are described in detail in the following description, will contribute to the overall noise reduction when combined with the foregoing procedures and devices, whereby the possibility of hearing impairment will be substantially reduced since the noise levels will be suppressed at the source as opposed to during their transmission or at the receiver. Thus, the necessity of enclosing the production portions of the machine, together with the attendant problems as a result of heat build-up are avoided, while the machine attendants will no longer be encumbered by earplugs or ear muffs, which can be a source of danger particularly in the event of an emergency in a plant.